// Copyright 2017 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "src/base/page-allocator.h"

#include "src/base/platform/platform.h"

namespace v8 {
namespace base {

#define STATIC_ASSERT_ENUM(a, b)                              \
    static_assert(static_cast<int>(a) == static_cast<int>(b), \
        "mismatching enum: " #a)

    STATIC_ASSERT_ENUM(PageAllocator::kNoAccess,
        base::OS::MemoryPermission::kNoAccess);
    STATIC_ASSERT_ENUM(PageAllocator::kReadWrite,
        base::OS::MemoryPermission::kReadWrite);
    STATIC_ASSERT_ENUM(PageAllocator::kReadWriteExecute,
        base::OS::MemoryPermission::kReadWriteExecute);
    STATIC_ASSERT_ENUM(PageAllocator::kReadExecute,
        base::OS::MemoryPermission::kReadExecute);

#undef STATIC_ASSERT_ENUM

    PageAllocator::PageAllocator()
        : allocate_page_size_(base::OS::AllocatePageSize())
        , commit_page_size_(base::OS::CommitPageSize())
    {
    }

    void PageAllocator::SetRandomMmapSeed(int64_t seed)
    {
        base::OS::SetRandomMmapSeed(seed);
    }

    void* PageAllocator::GetRandomMmapAddr()
    {
        return base::OS::GetRandomMmapAddr();
    }

    void* PageAllocator::AllocatePages(void* address, size_t size, size_t alignment,
        PageAllocator::Permission access)
    {
        return base::OS::Allocate(address, size, alignment,
            static_cast<base::OS::MemoryPermission>(access));
    }

    bool PageAllocator::FreePages(void* address, size_t size)
    {
        return base::OS::Free(address, size);
    }

    bool PageAllocator::ReleasePages(void* address, size_t size, size_t new_size)
    {
        DCHECK_LT(new_size, size);
        return base::OS::Release(reinterpret_cast<uint8_t*>(address) + new_size,
            size - new_size);
    }

    bool PageAllocator::SetPermissions(void* address, size_t size,
        PageAllocator::Permission access)
    {
        return base::OS::SetPermissions(
            address, size, static_cast<base::OS::MemoryPermission>(access));
    }

    bool PageAllocator::DiscardSystemPages(void* address, size_t size)
    {
        return base::OS::DiscardSystemPages(address, size);
    }

} // namespace base
} // namespace v8
